Wheel dresser



April 16, 1957 w. J. NEwELL 2,788,624

WHEEL DRESSER Filed July 29, 1955 2 Sheets-Sheet l INVENTOIL W/u/JM J/Vfwfu Arran/frye April 16, 1957 w. J. NEWELL 2,788,624

WHEEL DRESSER Filed July 29, 1955 2 ShSBtSfShSet 2 IN VEN TOR.

W/z/AM J /VfwaL www@ ,4 T TOR/VE y WHEEL Dnnssnn William J. Newell,Lakewood, Ohio, assignor to Harris- Seybold Company, Cleveland, Ohio, acorporation of Delaware Application July 29, 1955, Serial No. 525,114

9 Claims. (Cl. 51m-238) This invention relates to improvements in wheeldressers, that is to say mechanisms for dressing to the desired contourthe active surfaces of grinding wheels. This application is acontinuation-in-part of my former application Ser. No. 308,761, ledSeptember l0, 1952, now abandoned.

` One of the objects of the invention is the provision of a wheeldressing attachment for a grinding machine of the type in which the toolor other work to be ground is mounted between centers arranged on a lineat iight angles to the plane of the grinding wheel.

Another object is the mounting of the dressing tool on a slide which isgiven a slight swinging movement about a pivot point which travelslengthwise as the template produces the swinging movement.

Another object is the provision of a wheel dressing unit adapted to bemounted between centers spaced apart the correct distance to take theholder for the work to be ground, the dressing tool being disposed inthe dressing unit at the same point longitudinally of the unit as theWork in the work holder, whereby the dresser and the work may beinterchangeably mounted in the machine with a minimum of adjustment.

Still another object is the provision of a novel spring means forholding the slide in operative engagement with the template.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, I have illustrated in the accompanyingdrawings, in which: Y

Fig.` l is a plan view of my wheel dressing unit.

Fig. la is a fragmental detail view on a somewhat larger scale.

Fig. 2 is a transverse sectional View taken substantially on the line 22 of Fig. l.

Fig. 3 is a transverse sectional view taken substantially on line 3-3 ofFig. l.

Fig. 4 is a plan view of a work holder for the work to be ground by thedressed wheel, the work being shown in position thereon, and

Fig. 5 is a longitudinal section taken substantially on the line 5-5,Fig. 4.

The invention is illustrated herein as applied to a dressing attachmentfor a grinding machine in which the grinding wheel is dressed to acontour required for the cutters of a reaming tool. However in some ofits aspects the invention is susceptible of more or less generalapplication for the contouring of grinding wheels. In the illustratedcase reaming cutters with their holder are shown by way of example inFigs. 4 and 5.

In these figures there is shown at a holder provided with center holes11 and 12 adapted to be engaged by a headstock center indicated at 13and a footstock center indicated at 14 respectively. The holder 10 isprovided with a transverse way 15 in which is tixed by means of a screw16 and dowels 17 a block 18 having a centering projection 19. A bar 20provided with a recess to t atent projection 19 is mounted at the bottomof way 15 abutting block 18. This bar is clamped in position againstblock 1S by a plate 21 which has a hat face engaging one side of theplate and an inclined face 22 engaging a similarly inclined face 23 onthe holder. The clamping plate 21 is arranged to be drawn down andtoward the bar 20 by the bolt 24 having a wing nut 25, a coil spring 26being disposed in a cavity surrounding the bolt for raising the boltwhen the nut is loosened.

Cutters 27 and 28 are mounted in diagonally disposed grooves 29 and 30formed in bar 20. Their positions in the grooves may be adjusted bybacking screws 3l, and they are secured in adjusted position by screws32 the heads of which engage washers 33 that extend into rabbets 34formed in the cutters. The grinding wheel is shown at 35. The centers 13and 14 may be moved t0- ward and away from the grinding wheel byconventional means, not shown. It will be understood that when theworking surfaces of the cutters 27 and 28 have been ground in a grindingmachine having the centers 13 and 14 and a grinding wheel 35 positionedas indicated in Fig. 4, the cutter assembly may be removed from themachine and mounted in a reaming machine, not shown, for performing areaming operation.

Referring now to Figs. l to 3 inclusive, the same centers of thegrinding machine are indicated at 13 and 14, and the grinding wheel at35. A bar 36, hereinafter termed a track bar, preferably of the samelength as the holder 1i), is similarly provided with center holes 37 and3S to receive the centers 13 and 14 respectively. To

steady the bar 36 and prevent it from turning clockwise as viewed inFig. 2 there is attached to the bottom of the bar an arm 39 which isdisposed to bear upon the top of a rail 4t) in the bed of the grindingmachine.

41 is a slide which is of inverted channel shape throughout the majorpart of its length, the side elements of the channel being interiorlyspaced a distance suiicient to leave clearance between the slide and thebar 36, as indicated in Figs. 2 and 3. Side rails 42 and 43 are securedto the side members of the channel and. extend beneath and slidablyengage track bar 36. On the side of the slide 41 facing the grindingwheel there is a projection 44 in which is mounted a diamond dressingtool 45 xed in position by a setscrew 46.

On the upper side of the bar 36 near one end thereof there is mounted ahardened bearing block 47 which is securely fastened in place by a screw48 and a pair of dowel pins 49. Near the opposite end of the bar thereis a hardened template block 50 secured in place by a screw 51 and pins52, this block having a cam profile surface 53 on one side thereof. Theopposite side of block 5t) is recessed and provided near its ends withbearing surfaces 54 against which is a ilat leaf spring 55 bears. Thisspring is held in place against endwise movement by projecting portions56 of the block.

Means is provided for a slow even traverse of the slide 41 on the bar36. This may be accomplished by the mounting of a rack 58 on bar 36 inmesh with a pinion 59 secured to a shaft (it) that is journaled in anenlargement 61 on the slide. Shaft 6d also carries a worm wheel 62 withwhich meshes a worm 63 pinned to a shaft 64 upon the outer extremity ofwhich is a wheel 65 carrying a handle 66, by means of which the worm maybe turned for causing pinion 59 to travel over rack 58 and thereby movethe slide in one direction or the other. The travel of the slide isnecessarily slow because of the gearing down provided by the worm andworm wheel drive, and hence the operation of the dressing tool is easilycontrolled and accidental rapid travel is presented. A slot 63 is formedin one side wall of the slide 41 and a screw 69 extends through thisslot and is threaded into a tapped hole in bar 36, by means of which thetravel of the slide is limited and accidental disassembly of the partswhen the unit is not in the machine is avoided.

ln the upper portion of the slide al near the right hand end lthereof asviewed in the drawing there are mounted two ball bearing rollers 70 and7l. directly opposite each. other and spaced apart a distance onlyslightly greater than the width of bearing block 47. it should beunderstood that balls or other rounded followers could be substitutedfor the rollers 70 and '71, the purpose being to effect line or pointengagement resulting in effect in a moving pivotal mounting for theslide.

As the slide travels back and forth upon the track bar 36 these wheelsroll upon the block i7 and in effect form a movable pivot for the slide.Near the Oppositeend of the slide there are mounted in the upper.portion thereof two other ball bearing rollers 72 and 73. Roller 72runs upon the Vprofile surface 53 of template block 5t), while Vroller73 runs upon leaf springS. The'snacing of rollers 72 and 73 is such thatwhen theroller 72 is in'engagement with the highvpoint of the profilesurface 53 leaf `spring 55 isflexed. When the Vrollers approach eitherend of the template block the flexing of the spring decreases, butin allpositions roller 72 is held rmly against the cam surface 53.

During cndwise travel of the slide, roller 72 running on cam surface 53causes the left hand end of the slide to move transversely, swinging theslide to a slight extent upon its pivotal mounting provided by therollers 7G, 7l engaging the bearing block 47. The clearance betweentrack bar Eli/sand the side walls of the slide is provided in order toaccommodate this swinging motion.

As will be apparent from the preceding description, the wheel dressingunit and the cutter mounting are interchangeably carried by the centersof the grinding machine, whereby the dressing unit may first be mountedon these centers and the dressing tool moved across the face of thewheel to produce the 'desired contour andthereafter the rea-ming cuttersand their support may be mounted as a unit on the same centers and thecutters may be swung about thesecenters into contact with the wheel,without relative movement of the wheel and critters along. the line ofcenters, for grinding them with a contour comple'men tary to the contourof the dressed wheel.

Thus a novel an'd Vhighly accurate `and efficient method of grindingroaming cutters of the type described is employed.

As is well known in the art, reai'ners of this type `(known asfloatingreamers since only two cutters are used and these are mounted atopposite ends of a support bar vwhich is self centering as it is rotatedwithin 'the hole being'reamed) 'must be 'ground with a lead angleportion, a straight portion and a back taper portion and with backclearance behind all three of these portions of the cutting edge.Accuracy in allthese respects is very important.

Heretofore the manner of grinding such cutters has been to grind each ofthese three portions of the cutting edge Vseparately by the manualsetting of an adjustable cutter holder at `the desired angle and thenthe motion of the holder along the ways of the grinding machine to carrythe cutter past the grinding wheel. For veach portion of the cuttingedge at least two passes of the cutter past the wheel were required,with the cutter and wheel adjusted to slightly different positions, inorder to get socalled primary and secondary back clearance. rfhus sixdistinct manual operations have heretofore been required which consumemuch time and necessitate a high degree of skill on the part of theoperator. The possibility of errors and improper' finish iscorrespondingly high.

In contrast to past procedure, themethod of this invention involvesmounting a dressing unit between the centers-of the grinding machine,`dressing the Ydesired contour into the face of the grinding wheel bythe motion of the dressing tool along and transversely to the line ofcenters, and, after removal lof the dressing unit, mounting the cuttersand' their support lbaron the same centers and in line with the dressedwheel and swinging the cutters into vctritait"with the wheel yto`g`rindth`inwitha cbiitoiir complementary to that of the wheel.

ln practice and as shown in the drawing the cutters are so mounted as tobe spaced vertically a short distance above the line of centers so thata desired amount of radial back clearance is provided behind allportions of the cutting edge as the cutters move past the grindingwheel.

The method and device of the invention provide large savings in time ofgrinding, `superior surface fnishin'the reamed hole, higher ratio offeed and -less downtime of production equipment for correction oferrors.

Having thus described my invention, I claim:

l. In a grinding machine, a grinding wheel, a wheel dressing unitmounted adjacent tothe wheel to be dressed, comprising a track bar withits lengthwise dimension at an angle to the plane of the wheel, a slidereciprocable on the'track bar, a wheel dressing tool -tired-in saidslide, a bearing block on said bar Vnear one endthereoa template blockon said bar near the opposite end thereof, said template block having acurved profile surface on One side thereof, a pair -of opposed rollersmounted on 'said slide engaging opposite sides of said bearing block toprovide a-travelingpivot for the slide, a'follower-on said slideengaging said profile surface, means holding said follower innf'sngager'nent with said profile surface during movement of the slide,and means operatively connected to'said slide for slowly traversing saidslide over Asaid track bar, whereby the wheel may be dressed to acontour governed by saidprolile surface.

2. vIn a grinding machine of the typein which the work is mountedbetween centers, a wheel dressing unit comprising a ytrack bar mountedbetween said centers, a slide reciprocable on said track bar, a wheeldressing tool fixed in said slide,la bearing block mounted on said trackbar near one end thereof and a template block mounted on thebar near theopposite `end thereof, said template block having a prole surface on oneside land a `leaf spring on the other, -a pair of opposed rollersmounted on said slide engaging opposite sides of said bearing block toprovide a traveling pivot for the slide, a second pair of opposedrollers mounted on'said slide one roller engaging saidtemplate surfaceand the other on saidsplin'g, and means operatively connected to saidslide for moving said slide lengthwise of said track bar, whereby thewheel may be dressed to a contour governed by the profile surface sofAsaid template.

3. In a grinding machine of the type in which the Work is mountedbetween centers, a'wheel dressingunit comprising a track barmountedbetween the centers -of the machine, a bearing block mounted on theuppersurface of said track Vbar near one end of the latter, a templateblock mounted on the upper surface of the Vbar near the opposite endthereof, "said template block having a profile surface on one sidethereof and a leaf spring supported at its lends in 'the block at theother side thereof, a slide of inverted channel shape embracing saidtrack bar and movable lengthwise thereon, said slide carrying a pair ofopposed rollers bearing on opposite sides of said bearing block andcarrying a second pair of opposed rrollers bearing upon said profilesurface and said leaf spring, 'a dressing tool fixed in said slide, andmeans operatively connected to said slide for slowly traversing said`slide`over lsaid track bar, whereby the wheel may be dressed toacontour governed by said profile surface.

4. Ina grinding machine of the type in which the work is mounted betweencenters, a wheel dressing unit c'omprising a track bar mounted betweenthe centers 'of the machine, a slide reciprocable on the track bar,means at one end of the unit constituting a` pivot for thev slideInovable lengthwise on the track bar, a template block 'mounted on thetrack bar"near the opposite end thereof, said template blockhavingaprolesurface on vone side thereof, a leaf 'spring supported Iat its ends inthe' block "at the other 'side thereof,v saidslide carrying a pair ofopposed assenze rollers bearing upon the said profile surface and thesaid leaf spring, a dressing tool fixed in said slide, and meansoperatively connected to said slide for slowly traversing said slideover said track bar, whereby the wheel may be dressed to a contourgoverned by said prole surface.

5. In a grinding machine, a wheel dressing uni-t mounted adjacent to thewheel to be dressed, comprising a track bar with its lengthwisedimension at right angles to the plane of the wheel, a slidereciprocable on the track bar, a wheel dressing tool fixed in saidslide, means at one end of the unit constituting a pivot for the slidemovable on the track bar lengthwise of the unit, a template blockmounted on the track barnear the opposite end thereof, said templateblock having a profile surface on one side thereof and a leaf springsupported at its ends in the block at the other side thereof, said slidecarrying a pair -of opposed rollers bearing upon the said profilesurface and the said leaf spring, and means operatively connected tosaid slide for slowly traversing said slide over said track bar, wherebythe wheel may be dressed to a contour governed by said prole surface.

6. In a grinding machine, a wheel dressing unit mounted adjacent to thewheel to be dressed, comprising a track bar, a slide reciprocable on thetrack bar, a wheel dressing tool fixed in said slide, a bearing blockmounted on 4said track bar near one end of the latter, a template blockmounted on the track bar near the opposite lend thereof, said templateblock having a profile surface on one side thereof and a leaf springsupported at its ends in the block at the other side thereof, said slidecarrying a pair of opposed rollers bearing on opposite sides of saidbearing block and carrying a second pair of opposed rollers bearing uponthe profile surface and upon said leaf spring, and means operativelyconnected to said slide for slowly traversing said slide over said trackbar, whereby the wheel may be dressed to a contour governed by saidprotile surface.

7. Dressing apparatus for the grinding wheel of a grinding machine,comprising a track bar, a slide reciprocable on the track bar, a wheeldressing -tool fixed in said slide, a bearing block on said bar near oneend thereof, a template block on said bar near the opposite end thereof,said template block having a curved profile surface on one side thereof,a pair of opposed rollers mounted on said slide engaging opposite sidesof said bearing block to provide a traveling pivot for the slide, afollower on said slide engaging said prole surface, means holding saidfollower in engagement with said profile surface during movement of theslide, and means operatively connected to said slide for slowlytraversing it over said track bar, whereby the wheel may be dressed to acontour governed by said profile surface.

8. The method of grinding to an accurate curved contour the workingsurface of each of a pair of reaming cutters which during the reamingoperation are mounted at opposite ends of a support bar, comprisingmounting a wheel dressing unit on aligned work supporting centers of agrinding machine having a grinding wheel adjacent the line of saidcenters, dressing said grinding wheel to a curved contour by motion ofthe dressing tool of said unit along and transversely to the line ofsaid centers in a curved path extending across the surface of saidwheel, removing said dressing unit from said centers, mounting said pairof cutters and their support bar as a unit on said centers with theworking surfaces of `said cutters at substantially equal distances fromthe line of said centers and in xed longitudinal vposition in line withthe dressed curved surface of said wheel, and grinding both cutterswhile thus mounted by movement thereof about said centers into contactwith said wheel.

9. For use in a grinding machine having a pair of centers spaced apart agiven distance vbetween which centers the work to be ground may bemounted in a given transverse plane for rocking movement about saidcenters in fixed longitudinal relation thereto and having a grindingwheel mounted to rotate in said given transverse plane to one side ofthe line of said centers; a wheel dressing unit comprising a track barprovided with mounting means at its ends spaced apart said givendistance as aforesaid for supporting the bar on centers spaced apartsaid given distance with the lengthwise di'- mension of the barextending along a line joining said mounting means, a templet blockmounted on the track bar and having a cam profile surface, a wheeldressing tool, a mounting supporting said tool on said track bar forlimited movement of the tool lengthwise of and transversely to saidtrack bar across the grinding surface of a wheel disposed relative tosaid mounting means in a position corresponding to the position of thegrinding wheel of the machine relative to the centers of the machine asaforesaid, a follower on said mounting in fixed relationship to saidtool and engaging said profile surface, means for holding said followerin engagement with said prole surface during movement of said toollengthwise along said track bar, and means for moving the mountinglengthwise on said track bar, whereby the wheel of the grinding machinedisposed in said given transverse plane may be dressed to a contourgoverned by said profile surface when said track bar is mounted betweenthe centers of the grinding machine.

References Cited in the tile of this patent UNITED STATES PATENTS850,014 Johnston Apr. 9, 1907 1,530,357 De Jong Mar. 17, 1925 1,937,961Hutchinson Dec. 5, 1933 2,220,647 Harley Nov. 5, 1940 2,348,354 MillerMay 9, 1944 2,373,187 Johanson Apr. 10, 1945

